Even if the signal only held for a few seconds, it was enough to let them know their loved ones were OK. But most said they've had no luck, and it's tough to stay optimistic.
"Earthquakes are part of the Japanese culture. We are trained very early to react to them properly and not panic. But something like a 9.0 is beyond human comprehension," said Kei Akagi, a college music professor and a Japanese native.
Akagi now lives in Orange County, but he grew up in Sendai. When he saw the images of the tsunami's destruction, his first thought was of his family still living on Japan's northern coast.
"I managed to contact my sister a few hours ago. Telephone communication was very spotty there. I don't know what happened to some of my other relatives in the area," he said.
Search-and-rescue efforts continued in northeastern Japan Monday. It's an agonizing time for many local Japanese-Americans and others with loved ones in the disaster area.
Many of them live in or frequent the Little Tokyo area of Los Angeles.
Making contact with people in the disaster area in Japan is still very difficult. Phone service in many parts of Japan is still down. Social networking is one of the ways people are staying in contact.
One local woman's son is stranded in Japan.
When word of the massive earthquake and tsunami hit televisions around the world, Debbie Golden's heart skipped a beat.
"My son lives 20 miles north of Sendai," said Golden.
Alex, 24, is in Japan teaching English. He has two separate mobile phones, but Golden was unable to reach him. She started to panic, until two simple words popped up on Alex's Facebook page: "I'm OK."
"I just burst into tears of happiness," said Golden.
Try as she might, Golden still can't reach Alex by phone, but he has been able to post a couple more messages.
Alex's latest Facebook post read: "I'm OK. No injury. I have food water car half a tank of gasoline. In no danger of tsunami. Apartment still standing with water. Limited communication."
"He was able to post on Facebook that he was unhurt and safe, and he was asking that somebody call the embassy and tell them to get him out," said Golden.
But even though Golden's son is stranded in tough conditions, he's alive.
Others with loved ones in the disaster zone aren't that lucky.
Nana Snyder grew up in southern Japan. Her family is safe but a family friend is feared dead.
"He's a fisherman," said Snyder. "And he went fishing. And they don't know exactly where he is. It's so sad."
Golden says getting Alex back could take weeks. All the roads to his small town have been wiped out or were closed. Golden says the U.S. State Dept. has no current plans for extractions. Japanese authorities are completely overwhelmed with rescue efforts.
Golden is just happy her son is safe.
As the search continues, some restaurants in Los Angeles' Little Tokyo are collecting what they can to send to victims. About $3,000 was raised in a Little Tokyo fundraiser for earthquake victims over the weekend.